Present day electronic devices, particularly portable electronic devices such as, for example, smart phones and tablets can be equipped with a battery unit that comprises multiple rechargeable batteries or cells. The rechargeable batteries are electrically connected to each other to provide (or supply) an output voltage used to run the electronic device. Recharging of the battery unit requires providing a charge current to the battery unit. The maximum allowable value of the charge current is determined in accordance with the arrangement of the rechargeable cells, i.e., how they are electrically connected to each other, and in accordance with safety measures such as, for example, those set out by the International Association for the Wireless Communication Industry (CTIA), to ensure safety during the recharging process.
For example, under such safety measures, an electronic device powered by a battery unit having multiple rechargeable same cells electrically connected to each other, for example, in parallel could have, as its maximum allowable charge current, the maximum allowable charge current for a single cell. This would ensures that in the case where the multiple rechargeable cells become electrically disconnected and only one rechargeable cell remains connected to the recharging unit, that the charge current would still be safe for that single remaining cell. However, having this “safe” charge current leads to long recharging times particularly when all the rechargeable cells are in place and electrically connected to each other.
Improvements in portable devices that have a battery unit with multiple, electrically connected rechargeable cells are therefore desirable.